Angiogenesis is concerned with the occurrence or pathological processes of various inflammatory diseases (rheumatic diseases, psoriasis, etc.) diabetic retinopathy, tumors, and the like. Therefore, it has been considered that inhibition of angiogenesis or vascularization has a connection with the therapy and prophylaxis of such diseases. A number of research groups have searched for compositions which prevent or inhibit vascularization. For example, EP-A-359,036, EP-A-357,061, EP-A-354,787, EP-A-386,667 and EP-A-415,294 disclose that fumagillol derivatives have excellent vascularization inhibition activity and they also disclose processes for the production thereof. Some of these fumagillol derivatives have low water-solubility. Accordingly, it is desirable to obtain suitable means for enhancing water-solubility to facilitate administration and to obtain more effective pharmacological activity.